curl: rename "transform" to "amend_secrets"

The curl source is the only source left that uses "transform". And
here the name is very generic but in fact we only do a single thing:
we add secrets for subscriptions for for mtls to the download.

So rename to make it clear what this is all about.

sources/org.osbuild.curl

@@ -102,29 +102,30 @@ class CurlSource(sources.SourceService):
         super().__init__(*args, **kwargs)
         self.subscriptions = None
 
-    def transform(self, checksum, desc):
-        url = desc
-        if not isinstance(url, dict):
-            url = {"url": url}
+    def amend_secrets(self, checksum, desc_or_url):
+        if not isinstance(desc_or_url, dict):
+            desc = {"url": desc_or_url}
+        else:
+            desc = desc_or_url
 
-        # check if url needs rhsm secrets
-        if url.get("secrets", {}).get("name") == "org.osbuild.rhsm":
+        # check if desc needs rhsm secrets
+        if desc.get("secrets", {}).get("name") == "org.osbuild.rhsm":
             # rhsm secrets only need to be retrieved once and can then be reused
             if self.subscriptions is None:
                 self.subscriptions = Subscriptions.from_host_system()
-            url["secrets"] = self.subscriptions.get_secrets(url.get("url"))
-        elif url.get("secrets", {}).get("name") == "org.osbuild.mtls":
+            desc["secrets"] = self.subscriptions.get_secrets(desc.get("desc"))
+        elif desc.get("secrets", {}).get("name") == "org.osbuild.mtls":
             key = os.getenv("OSBUILD_SOURCES_CURL_SSL_CLIENT_KEY")
             cert = os.getenv("OSBUILD_SOURCES_CURL_SSL_CLIENT_CERT")
             if not (key and cert):
                 raise RuntimeError(f"mtls secrets required but key ({key}) or cert ({cert}) not defined")
-            url["secrets"] = {
+            desc["secrets"] = {
                 'ssl_ca_cert': os.getenv("OSBUILD_SOURCES_CURL_SSL_CA_CERT"),
                 'ssl_client_cert': cert,
                 'ssl_client_key': key,
             }
 
-        return checksum, url
+        return checksum, desc
 
     @staticmethod
     def _quote_url(url: str) -> str:
@@ -135,10 +136,10 @@ class CurlSource(sources.SourceService):
 
     def fetch_all(self, items: Dict) -> None:
         filtered = filter(lambda i: not self.exists(i[0], i[1]), items.items())  # discards items already in cache
-        transformed = map(lambda i: self.transform(i[0], i[1]), filtered)  # prepare each item to be downloaded
+        amended = map(lambda i: self.amend_secrets(i[0], i[1]), filtered)
 
         with concurrent.futures.ThreadPoolExecutor(max_workers=self.max_workers) as executor:
-            for _ in executor.map(self.fetch_one, *zip(*transformed)):
+            for _ in executor.map(self.fetch_one, *zip(*amended)):
                 pass
 
     def fetch_one(self, checksum, desc):

sources/test/test_curl_source.py

@@ -36,7 +36,7 @@ def test_curl_source_exists(sources_module):
     assert curl_source.exists(checksum, desc)
 
 
-def test_curl_source_transform(sources_module):
+def test_curl_source_amend_secrets(sources_module):
     sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
     curl_source = sources_module.CurlSource.from_args(["--service-fd", str(sock.fileno())])
     tmpdir = tempfile.TemporaryDirectory()
@@ -58,13 +58,13 @@ def test_curl_source_transform(sources_module):
         cm.callback(cb)
         checksum = "sha256:1234567890123456789012345678901234567890909b14ffb032aa20fa23d9ad6"
         pathlib.Path(os.path.join(tmpdir.name, checksum)).touch()
-        new_desc = curl_source.transform(checksum, desc)
+        new_desc = curl_source.amend_secrets(checksum, desc)
         assert new_desc[1]["secrets"]["ssl_client_key"] == "key"
         assert new_desc[1]["secrets"]["ssl_client_cert"] == "cert"
         assert new_desc[1]["secrets"]["ssl_ca_cert"] is None
 
 
-def test_curl_source_transform_fail(sources_module):
+def test_curl_source_amend_secrets_fail(sources_module):
     sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
     curl_source = sources_module.CurlSource.from_args(["--service-fd", str(sock.fileno())])
     tmpdir = tempfile.TemporaryDirectory()
@@ -78,5 +78,5 @@ def test_curl_source_transform_fail(sources_module):
     checksum = "sha256:1234567890123456789012345678901234567890909b14ffb032aa20fa23d9ad6"
     pathlib.Path(os.path.join(tmpdir.name, checksum)).touch()
     with pytest.raises(RuntimeError) as exc:
-        curl_source.transform(checksum, desc)
+        curl_source.amend_secrets(checksum, desc)
     assert "mtls secrets required" in str(exc)